1. Field of the Invention
The present invention relates, generally, to testing apparatus and methods. More particularly, the invention relates to electromechanical testing apparatus for measuring the spring rate of leaf springs used on automobiles.
2. Background Information
Balancing a car optimizes performance, particularly the cornering characteristics of a racing class automobile. The traction, adherence or grip between the tires and the track at each end of a car is proportional to the percentage of the weight at that end of the car. A car's grip is optimized when both the front tires and the rear tires begin to slide at the same time and at the same rate, resulting in the car having responsive, near-neutral handling characteristics. However, if the front tires slide first, the car tends to understeer and slide off of the track, and if the rear tires slide first, the car tends to oversteer and spin.
Numerous factors contribute to the near-neutral handling characteristics of a balanced car, including tires, wheel alignment, suspension, weight distribution, center of gravity and aerodynamics. A properly suspended car has more braking and acceleration control when the car is moving in a straight line and more steering control when the car is maneuvering around corners. A leaf spring suspension exerts resistance against up and down movement by the flexing action of leaf springs. One end of a leaf spring is rigidly mounted to the frame as both the axle end and the shackle location of the leaf spring freely move with the rising and falling of the wheel. The leaf spring flexes and absorbs shocks when the wheel rises.
Leaf springs have a spring rate that identifies the amount of resistance that it provides against up and down movement. This spring rate may change over time and may change because of use. It is therefore desirable to be able to accurately measure the spring rate of leaf springs in order to calculate the resistant force, balance the car, and ultimately improve the handling characteristics of the car.
Applicant's invention provides an apparatus and method for testing and measuring the spring rate of leaf springs which is believed to constitute an improvement over existing technology.